In the development of nuclear power station generators, there is an increase in the demand for safety measures. Presently, the specifications of regulatory authorities are stipulating safeguards requiring that all the equipment associated with the nuclear power generating station successfully resist present and anticipated physical stresses and hostile environments such as those produced by seismic disturbances and loss of coolant accidents.
Attention is now focused on the rack required to support devices such as signal transducers and transmitters. These transducers and transmitters are important links between the primary sensing and control elements and the instruments and controls centralized for supervision by personnel. The primary sensing elements for variables, such as temperature, level, flow and pressure, are dispersed widely throughout the nuclear power generating station. The flows of particular concern are those of pumps and primary fluid systems throughout the installation. Many fluid levels are to be sensed and controlled. Temperatures are to be monitored and maintained within prescribed limits. Pressures must be sensed and regulated in a myriad of locations. Of particular concern are the high pressure boundaries in piping throughout the installation. Throughout the system, there are groups of signal transducers and transmitters which relay the primary element signals to the control room and deliver responsive control signals from the control room to valves and other regulatory devices. These transducing and transmitting devices, along with the conduits, valves and piping associated with them, must be mounted with the utmost dependability, accessibility and flexibility.
The rack for signal transducers and transmitters is subject to the most rigid technological standards of governmental regulatory agencies. Fundamentally, the rack must perform its support function during normal operation, during any accident within the installation, and during any post-accident period. It has now developed that there is a need for flexibility in the rack not heretofore provided by the prior art. There is a demand for changes in the number and mounting of transducers and transmitters after the original installation of the rack. There remains a need for parts of the rack to be permanent in order to preserve the stability and dependability of the rack in its simple support function. However, experience is dictating the need for provisions with which to modify the rack to accommodate changes in the number and mounting of transducers and transmitters. Meanwhile, the sturdy rack must not require maintenance, such as painting, but must successfully resist any strain of forces from its environment.